Fireplace heating channel

ABSTRACT

This invention is designed to increase the heating efficiency of an existing conventional fireplace. The device consists of a hollow metal air conveying channel which is designed to fit closely against the multiple inside walls of an existing fireplace in combination with a hollow metal flame guide vane that connects the upper inside portions of the side arms of the air channel. The vane is triangular in cross section and is positioned so as to form a hot gas passageway between the rear surface of the vane and the upper portion of the center panel of the air channel. The channel and vane are heated by the fire and room air is forced to make multiple horizontal passes through the fireplace heating channel, at option through the vane, by a blower. The heated room air being vented back into the room. The device is readily insertible in an existing fireplace and does not require modification to the fireplace structure and does not interfere with its normal functioning. Because of this feature the device is compatible with a broad range of existing fireplace sizes and types.

United States Patent Nelson FIREPLACE HEATING CHANNEL [76] Inventor: Clifford H. Nelson, 9 Merry Point Ter., Newport News, Va. 23606 [22] Filed: Jan. 21, 1974 [2]] Appl. No.: 434,978

[52] US. Cl. 126/121; 126/129; 126/131 [51] Int. Cl. F24b 7/00 [58] Field of Search 126/121, 128, 129, 130, 126/131 [56] References Cited UNITED STATES PATENTS 32,283 5/1861 Gauson 126/121 1,377,108 5/1921 Williams 126/121 [57] ABSTRACT This invention is designed to increase the heating efficiency of an existing conventional fireplace. The device consists of a hollow metal air conveying channel which is designed to fit closely against the multiple inside walls of an existing fireplace in combination with a hollow metal flame guide vane that connects the upper inside portions of the side arms of the air channel. The vane is triangular in cross section and is positioned so as to form a hot gas passageway between the rear surface of the vane and the upper portion of the center panel of the air channel. The channel and vane are heated by the fire and room air is forced to make multiple horizontal passes through the fireplace heating channel, at option through the vane, by a blower. The heated room air being vented back into the room.

1,488,195 3/1924 Dawson 126/121 I 2,052,643 9/1930 Modine 126/121 The devlce IS readlly msertlble m an exlstmg fireplace 2,359,197 4/1944 Brooks 126/121 and does not require modification to the fireplace 2,362,526 11/1944 Austin... 126/121 structure and does not interfere with its normal 3,190,282 6/1965 Bauer 126/131 functioning. Because of this feature the device is 3,762,391 10/1973 Andrews 1 126/121 compatible with a broad range of existing fireplace sizes and types. Primary ExaminerW1lliam F. ODea u Assistant ExaminerPeter D. Ferguson 7 Clalms, 8 Drawmg Flgules PATENTEBJUL29I975 3, 896.785

SHEET 1 FIG. 1

PATENTED JUL 2 91975 SHEET PATENTEI] JUL 2 9 I975 SHEET FIG] FIREPLACE HEATING CHANNEL DESCRIPTION OF THE PRIOR ART Presently on the market are various devices that use a fireplace to heat the room air by circulation. These designs involve a metal structure that is placed inside a fireplace. The heating of room air is usually achieved by circulation of room air through the device. The direction of this circulating air is mainly vertical. In a departure from prior art this invention employs multiple horizontal passes of forced air flow to heat the room air. In addition to being an efficient extractor of heat from the fireplace, this invention has a minimum impact on the original appearance and decor of the fireplace. Other novel features include a unique flame guide vane that recovers radiation normally lost up the fireplace throat, reduces room air losses to the chimney, has means of increasing transfer of heat from the fire to the subject device, and when compared to prior art this invention conserves and reduces the use of electrical power.

BACKGROUND OF THE INVENTION Our nation is currently faced with a projected shortage of energy derived from gas and fuel oil. This invention is directed toward reducing the use of these shortage fuels for heating individual houses.

Many American houses have fireplaces that could burn alternate fuels such as wood, coal and other combustibles, but because the efficiency of the conventional fireplace is low, use as an alternate heating source is marginal.

The Fireplace Heating Channel meets this need and transforms what has traditioanlly been primarily a deeorative feature of the house into a more efficient generator of useful heat.

SUMMARY OF THE INVENTION The Fireplace Heating Channel consists ofa metal air conveying channel designed to fit closely against the multiple inside walls of an existing fireplace and equipped with a flame guide vane. The channel and vane are heated by the fire. Room air is forced to make multiple horizontal passes through the fireplace heating channel, and at option through the vane, by a blower. The heated room air is vented back into the room, yielding a substantial increase in the overall heat output from the fireplace.

The installation of the device does not interfere with the normal functioning of the existing fireplace and requires no modification of the basic structure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic drawing of the preferred embodiment of the invention illustrating the three-sided air channel and the flame guide vane.

FIG. 2 is a schematic drawing of a simplified heating channel with only two adjoining sides and a flame guide vane.

FIG. 3 includes a schematic drawing of the threesided air channel and flame guide vane inserted within a conventional fireplace.

FIG. 4 is cross-section AA of FIG. 3.

FIG. 5 is cross-section BB of FIG. 3.

FIG. 6 is cross-section C-C of FIG. 3.

FIG. 7 is a schematic drawing of a three-sided air channel and flame guide vane utilizing three horizontal passes of room air through the channel and one pass through the vane with air discharging on the opposite end of the channel from the blower.

FIG. 8 is a schematic drawing of a three-sided air channel and flame guide vane with room air flowing through the channel but not through the guide vane.

DETAILED DESCRIPTION OF THE INVENTION FIG. I illustrates the principle embodiment of the invention, a free standing air channel 31 and flame guide vane 20 designed to efficiently heat room air flowing through the channel 31 and the vane 20. The air channel 31 is made of metal. It is an air conveying channel 31 designed to be insertible into an existing conventional fireplace without requiring modification to the basic fireplace structure. The air channel 31 shown in FIG. 1 has three sides 8, 9, 2 which fit against the three inside fireplace walls. The air channel 31 is U shaped, having a back 2, a left forward facing arm 8, and a right facing arm 9. The right arm 9 is shorter than the left arm 8. The front surface 2 of the channel 31 is separated from the back surface 1 by spacers 3, 4, 5. The spacers 3, 4, 5 are joined to the front 2 and back 1 surfaces in a manner to form air tight joints to prevent the entry of fire smoke and or the venting of room air from the channel 31.

The guide vane 20 extends from the upper portion of left arm 8 to right arm 9 and forms an air tight passage for room air between the two arms. The flame guide vane 20 is positioned so as to form a converging passageway for hot gases between it and the front surface 2 of the air channel and constructed wide enough to almost block the remainder of the fireplace throat leaving only a small gap between the guide vane and inside front surface of the chimney throat. The flame guide vane 20 is hollow and triangular, or other suitable shape, in cross section and made of metal.

The plenum chamber 6 receives the flow of room air generated by the blower 7 and directs it into the lower horizontal air passage 12 of the air channel 31. The baffle 10 indicated by dotted lines separates the left arm 8 and the back into two air passages, one upper 11 and one lower 12. The right arm 9 does not contain a baffie 10. The dot and dash line of FIG. I indicates the route followed by the flow of air in making two horizontal passes through the air channel 31. The room air enters the lower passage at 12 and when it reaches the right arm 9 is divided into two streams. One stream, indicated by a single dot and dash line, follows the upper passage of the air channel 31 and emerges at exit opening 1 1. The other stream, indicated by a double dot and dash line, passes horizontally through the flame guide vane 20 and also emerges at exit 11. When the air channel 31 and vane 20 are heated by a fire, radiant and fuel gas energy raises the temperature of the room air flowing through the air channel 31 and vane 20 which is returned to the room as useful heated air. In addition the heated surfaces of the guide vane and channel, that face the room, radiate heat energy into the room.

The air channel in combination with the guide vane is designed to increase the heat efficiency in several ways, thus providing an advancement over prior art, such as, (a) forming a converging passage to increase the transfer of heat from the hot ascending fuel gases to both the top portion of the center panel 'of the air channel 31 and the opposing inside surface of the guide vane 20 facing the center panel, (b) impede and greatly reduce the loss of excess room air up the chimney. which is a source of major loss of heat energy, the

- upper horizontal base of the triangular guide vane 20 is wide enough to nearly block the fireplace throat leaving only a converging passageway for hot fuel gases to the rear and a much smaller gap in front of the vane. (c) guide vane is designed to intercept, utilize and make available to the room a large portion of the heat radiation emanating upward from the fire to avoid its direct loss up the chimney throat, ((1) because the downward facing apex of the triangular cross sectioned guide vane 20 is much lower than the brick fireplace throat, most of the room air is forced to enter the fire more nearly at the combustion level where it is needed and the flow of undesired and excess room air is further reduced so as to increase the overall heat recovery from the fire, (e) The top horizontal surface of the guide vane is covered with heat insulating material to reduce loss of heat up the chimney, (f) the horizontal passes of circulating air through the center panel of the air channel represent an advancement over prior art, which employ a vertical partition in the center panel causing dead air spaces to be created by the circulating room air on each side of the vertical baffle, both in the upper and lower portions thereof, resulting in reduced transfer of heat energy to the circulating room air. In contrast the horizontal passes of the air in the subject invention enhances the transfer of heat to the circulating room air, in this center and hottest panel of the air channel, by eliminating dead air spaces, (g) with horizontal baffling, only one room air blower is required for air circulation as opposed to the two used in prior art resulting in conservation and reduced use of electrical power for operating the fireplace.

FIG. 2 is a schematic drawing of a simplified heating channel 32 with only two adjoining sides. It is similar in function to the air channel 31 shown in FIG. I but with the right arm 9 omitted. The channel 32 is sealed off with an end piece 22 at the place where the right arm 9 was attached as shown in FIG. 1. The baffle 10 has been shortened and does not extend all the way to the end piece 22. The room air flow route is indicated by the dot and dash line, originating at blower 7, passing through the plenum chamber 6, entering lower passage 12 and turning upward to pass between the end piece 22 and the shortened baffle 10 and then flowing back along the upper passage for exit through opening 11. The flame guide vane 20 functions are as described in FIG. 1, except that it does not have provision for room air to flow through it and accordingly its temperature increases providing more radiation energy to the room. The left end of the guide vane 20 is simply fastened to the inside of left arm 8 and the other end is supported by bracket 21. The bracket 21, in turn, is fastened to end piece 22. Other features are similar to those described in FIG. 1.

FIG. 3 is a schematic drawing illustrating the front view ofa conventional fireplace 17 with the three-sided air channel 31, plenum chamber 6, and blower 7 installed. During installation the air channel 31 is inserted under the fireplace arch l7 and fits against the inside fireplace walls. The baffle 10 is shown forming one upper air passage 11 and one lower air passage 12. The flame guide vane 20 is shown fastened to the upper inside arms 8 and 9 of the channel 31.

FIG. 4 is a schematic drawing of the cross section AA of FIG. 3, showing a plan view of a conventional fireplace 17, air channel 31, blower 7 and plenum chamber 6. The left arm 8 protrudes beyond the front face 17 of the fireplace and the air blower 7 and plenum chamber 6 are shown located on the front of the fireplace 17. The right arm 9 is shorter and does not extend beyond the fireplace front 17. The heat resistance insulating material 30 is shown attached all along the sides of the air channel 31 next to the inner walls of the fireplace 17 to reduce the loss of heat to the brick and masonry of the fireplace walls.

FIG. 5 is a schematic drawing of the cross section BB of FIG. 3. This cross section is a view looking toward the left arm 8 including a section of the back 1, 2 of the air channel 31 and a section of the flame guide vane 20 with heat resisting insulation 19 on the top surface. The plenum chamber 6 and blower 7 are shown located on the front face of the fireplace 17. To conform to the shape of a conventional fireplace, the back 1, 2 of the air channel is flat and contacts the rear wall of the fireplace at two places, at the floor level 33 and at the arch level 34. The left arm 8 is shown protruding beyond the fireplace front 17. The section of baffle 10 is shown. The insulation 30 covers the air channel surface 1.

FIG. 6 is a schematic drawing of the cross section CC of FIG. 3. The cross section is a view looking toward the right arm 9 including a section of the back 1, 2 of the air channel 31 and a section of the flame guide vane 20 with heat resisting insulation 19 on the top surface. A section of baffle 10 is indicated. The top right arm does not extend to the front face of the fireplace 17. The right arm 9 does not contain a baffle 10.

FIG. 7 is a schematic drawing of three sided air channel 31 that has three horizontal passes of room air. End pieces 28 and 29 seal off portions of the end of the air channel 31. The end openings remaining are 25, for receiving the room air from blower 7 and plenum chamber 6, and 27 for air venting into the room. Passage baffles 24 and 23 are shown by dotted lines. The route of air flow through the air channel is indicated by the dot and dash line. The room air is forced by blower 7 to make three horizontal passes of the air channel 31 before returning to the room through opening 27. As indicated by the double dot and dash line some of the room air during the final horizontal pass flows through the flame guide vane 20 to pick up added heat. The heat resisting insulation 19 that is placed on the upper surface of the guide vane 20 reduces heat loss up the chimney. The other general features of FIG. 7 are similar to those described in FIG. 1.

FIG. 8 is a schematic drawing of a free standing air channel 31 and flame guide vane 20. The function and description are similar to FIG. 1 with the exception that no room air flows through the flame guide vane. The guide vane is only attached to the air channel 31 arms 8 and 9 in which no air vents are cut. In this situation, the flame guide vane rises in temperature yielding heat to the room through increased radiant energy output. The design is simplified by omitting the flow of room air through the vane 20. Also, less soot collects on the vane 20 because of the higher temperature reached by the vane 20 without room air flowing through it.

Even though the invention has been described specifically relative to features such as: cross-sectional shape of the air channel back, air passage configurations, locations of the room air entry and exit passages, the location, shape and size of the left and right arms of the air channel, means of forcing air flow through the channel, the use of insulation, and the shape and location of the flame guide vane, it is to be understood that these features of the invention are the preferred embodiments only. There are many modifications and varia tions to the several features of the present invention that can be made, all without departing from the spirit or scope of the invention as is defined in the following claims.

I claim:

1. A free standing fireplace heating channel comprising a hollow metal air conveying channel in combination with a flame guide vane, insertible into an existing conventional fireplace without requiring modification to the fireplace structure, said channel having a center panel and at least one forward facing channel arm adapted to fit against multiple inside walls of a fireplace, said air channel having adjoining walls exposed to the heat from the fire with corresponding rear walls spaced therefrom and connected by spacer means so as to form a suitable air channel for conveying room air to be heated by the fire, means for forcing room air into a lower portion of said forward facing channel arm by a single blower, and baffle means to direct the forced circulating room air to make multiple horizontal passes through said channel prior to exiting back into a room from an upper portion of a forward facing channel arm as useful heating air, said guide vane being attached to an upper inside portion of said forward facing arm of said air channel and extending horizontally to a symmetrical position on an opposite side, said hollow metal guide vane having a triangular cross section with the base horizontal and the apex pointing downward toward the fire and positioned forward of the center panel of the air channel so as to form an upward converging passageway for the hot fire gases, said passageway being formed by the upper portion of a near vertical surface of the center panel and the opposing rearward slanting surface of the guide vane wherein the width of the horizontal base of the guide vane is constructed wide enough to almost block the remainder of the fireplace throat leaving only a small gap between the forward facing edge of the vane and the inside front surface of the fireplace throat, and insulation means for reducing heat losses from the horizontal base of said vane.

2. A fireplace heating channel as in claim 1, wherein the air channel equipped with a flame guide vane has three sides adapted to fit against the three inside walls of the fireplace.

3. A fireplace heating channel equipped with a flame guide vane as in claim 1, wherein a three sided air channel having first and second forward facing channel arms is adapted to fit against the three inside walls of an existing fireplace, wherein the three sided air channel has one horizontal baffle means that divides the first forward facing channel arm into an upper and lower air passageway and said baffle means is extended to also divide the rear or center panel of said channel into corresponding passages, such that room air enters the bottom portion of the first forward facing channel arm and then flows through the lower passageway of said center panel and turns upward and reverses flow in the second channel arm and subsequently returns to a room via the upper passageway so formed by the baffle means, further, said guide vane being fastened symmetrically to the inside walls of upper portions of the first and sec- 0nd forward facing channel arms, said vane having a hollow interior vented into the hollow interior of said channel arms at the point of attachment whereby said vane becomes an additional conveying channel for heating circulating room air.

4. A fireplace heating channel as in claim 1, wherein the air channel equipped with a flame guide vane, has two adjoining sides adapted to fit against two of the three inside walls of a fireplace.

5. A fireplace heating channel equipped with a flame guide vane as in claim 1, wherein a two sided air channel has one baffle means to obtain two horizontal passages for heating room air.

6. A fireplace heating channel equipped with a flame guide vane as in claim 1, wherein a three sided air channel having first and second forward facing channel arms is adapted to fit against the three inside walls of an existing fireplace, wherein said three sided air chan nel has two horizontal baffle means to obtain three horizontal passageways for heating room air in said channel and providing therewith for venting of heated room air from the upper forward portion of an opposite channel arm from that in which a lower air inlet is placed, said guide vane being fastened symmetrically to the inside walls of upper portions of the said first and second forward facing arms of said air channel, said vane having a hollow interior vented into the hollow interior of said channel arms at the point of attachment whereby said vane becomes an additional conveying channel for heating circulating room air.

7. A fireplace heating channel equipped with a flame guide vane as in claim 1, wherein a three sided air channel having first and second forward facing channel arms is adapted to fit against the three inside walls of an existing fireplace wherein the three sided air channel has one horizontal baffle means that divides the first channel arm into an upper and lower air passageway and said baffle means is extended to also divide the rear or center panel of said channel into corresponding pas sages, such that room air enters the bottom portion of the first forward facing channel arm and then flows through the lower passageway of said center panel and turns upward and reverses flow in the second channel arm and subsequently returns to a room from the upper portion of the first channel arm via the upper passageway so formed by the baffle means, further, said guide vane being fastened symmetrically to inside upper portions of said first and second forward facing channel arms and having no fluid communication with the interior of said air channel arms. 

1. A free standing fireplace heating channel comprising a hollow metaL air conveying channel in combination with a flame guide vane, insertible into an existing conventional fireplace without requiring modification to the fireplace structure, said channel having a center panel and at least one forward facing channel arm adapted to fit against multiple inside walls of a fireplace, said air channel having adjoining walls exposed to the heat from the fire with corresponding rear walls spaced therefrom and connected by spacer means so as to form a suitable air channel for conveying room air to be heated by the fire, means for forcing room air into a lower portion of said forward facing channel arm by a single blower, and baffle means to direct the forced circulating room air to make multiple horizontal passes through said channel prior to exiting back into a room from an upper portion of a forward facing channel arm as useful heating air, said guide vane being attached to an upper inside portion of said forward facing arm of said air channel and extending horizontally to a symmetrical position on an opposite side, said hollow metal guide vane having a triangular cross section with the base horizontal and the apex pointing downward toward the fire and positioned forward of the center panel of the air channel so as to form an upward converging passageway for the hot fire gases, said passageway being formed by the upper portion of a near vertical surface of the center panel and the opposing rearward slanting surface of the guide vane wherein the width of the horizontal base of the guide vane is constructed wide enough to almost block the remainder of the fireplace throat leaving only a small gap between the forward facing edge of the vane and the inside front surface of the fireplace throat, and insulation means for reducing heat losses from the horizontal base of said vane.
 2. A fireplace heating channel as in claim 1, wherein the air channel equipped with a flame guide vane has three sides adapted to fit against the three inside walls of the fireplace.
 3. A fireplace heating channel equipped with a flame guide vane as in claim 1, wherein a three sided air channel having first and second forward facing channel arms is adapted to fit against the three inside walls of an existing fireplace, wherein the three sided air channel has one horizontal baffle means that divides the first forward facing channel arm into an upper and lower air passageway and said baffle means is extended to also divide the rear or center panel of said channel into corresponding passages, such that room air enters the bottom portion of the first forward facing channel arm and then flows through the lower passageway of said center panel and turns upward and reverses flow in the second channel arm and subsequently returns to a room via the upper passageway so formed by the baffle means, further, said guide vane being fastened symmetrically to the inside walls of upper portions of the first and second forward facing channel arms, said vane having a hollow interior vented into the hollow interior of said channel arms at the point of attachment whereby said vane becomes an additional conveying channel for heating circulating room air.
 4. A fireplace heating channel as in claim 1, wherein the air channel equipped with a flame guide vane, has two adjoining sides adapted to fit against two of the three inside walls of a fireplace.
 5. A fireplace heating channel equipped with a flame guide vane as in claim 1, wherein a two sided air channel has one baffle means to obtain two horizontal passages for heating room air.
 6. A fireplace heating channel equipped with a flame guide vane as in claim 1, wherein a three sided air channel having first and second forward facing channel arms is adapted to fit against the three inside walls of an existing fireplace, wherein said three sided air channel has two horizontal baffle means to obtain three horizontal passageways for heating room air in said channel and providing therewith for venting of heated room air from the upper forward portion oF an opposite channel arm from that in which a lower air inlet is placed, said guide vane being fastened symmetrically to the inside walls of upper portions of the said first and second forward facing arms of said air channel, said vane having a hollow interior vented into the hollow interior of said channel arms at the point of attachment whereby said vane becomes an additional conveying channel for heating circulating room air.
 7. A fireplace heating channel equipped with a flame guide vane as in claim 1, wherein a three sided air channel having first and second forward facing channel arms is adapted to fit against the three inside walls of an existing fireplace wherein the three sided air channel has one horizontal baffle means that divides the first channel arm into an upper and lower air passageway and said baffle means is extended to also divide the rear or center panel of said channel into corresponding passages, such that room air enters the bottom portion of the first forward facing channel arm and then flows through the lower passageway of said center panel and turns upward and reverses flow in the second channel arm and subsequently returns to a room from the upper portion of the first channel arm via the upper passageway so formed by the baffle means, further, said guide vane being fastened symmetrically to inside upper portions of said first and second forward facing channel arms and having no fluid communication with the interior of said air channel arms. 